body,
html {
  padding: 0;
  margin: 0;
  position: relative;
  background-color: blanchedalmond;
  min-height: 100vh;
}

body::before {
  content: "before";
  width: 0;
  display: block;
  background-color: rgba(0, 0, 0, 0.5);
  text-indent: -999px;
  position: absolute;
}

body::after {
  content: "end";
  width: 0;
  display: block;
  background-color: rgba(0, 0, 0, 0.5);
  position: absolute;
  right: 0;
  top: 0;
  text-indent: -999px;
}

.demo{
  padding:15px;
  max-width: 100%;
}
.demo p {
  font-size: 16px;
}
.demo .title{
  font-size: 160px;
}